This controls where the libudev
library is installed. The library needs to be in /lib because it's used by Udev at boot
time, before /usr might be
available, and the default --rootlibdir is /usr/lib.

--libexecdir=/lib/udev

This controls where Udev-internal rules and helper programs
are installed.

--disable-*

These options prevent Udev from installing helper programs
and other extras which require more external libraries. These
libraries are not part of the base LFS system. See the Udev
README file for more
information.